TRAILER.MANFD 1-1 1960 THRU 7-31 1962.POSSIBILITY THAT INDUCTION HARDENINGPROCESS IN EFFECT AT NORTH-AMERICAN ROCKWELL'S AXLE PLANT MAY HAVE CREATED HIGHRESIDUAL STRESSES AT INNER BEARING SHOULDER AREA.STRESSES MAY TURN INTOPHYSICAL CRACKS UNDER EXTENDED FIELD SERVICE. CONTINUED USE OF AXLE AFTERCRACKING MAY CAUSE AXLE SPINDLE TO FRACTURE.(CORRECT BY INSPECTING ANDREPLACING WITH NEW AXLE.).